Show/Hide All Child Rows and Child Row Formatting

This test case includes sample child rows that are all opened on table initialization: live.datatables.net/putarafo/3/edit

I added the button "Hide All Child Rows" that removes all child rows when clicked and then changes to "Show All Child Rows".

2 Questions:

1) This functionality works fine on the current page, but when you go to any other page or change the number of rows to show, further child rows remain opened. How can all child rows be opened and closed (and stay so) on all pages throughout my datatable?

2) In the format(d) function, how could I change the color of individual strings by a condition? For example, if 'a' is included in the string, this letter should be red, else it should be black.